FELIX and SW ROD Commissioning of the New ATLAS Readout System

After a successful period of data-taking concluded in 2018, the ATLAS experiment is being upgraded with the goal of consolidating and improving its physics performance. The upgraded detector systems will be complemented by a new readout chain with main components: the Front-End LInk eXchange (FELIX) and the Software ReadOut Driver (SW ROD). The FELIX system is comprised of commodity servers equipped with one or more FPGA-based PCIe cards and a high speed network interface. Each FELIX node acts as a router between the detector front-end custom links and the switched network. Commodity servers connected via the network constitute the SW ROD infrastructure. Each SW ROD node runs a multi-threaded software tasked with data aggregation, buffering, detector-specific processing, and routing to the online event filter. This presentation covers the commissioning of FELIX and SW ROD for the restart of the detector operations scheduled for early 2022.